Process for the destructive hydrogenation of carbonaceous substances



Patented Jan. 17, 1933 UNITED STATES PATENT, OFFICE J'OSEF VARGA, OFBUDAPEST, HUNGARY, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE FIRM OFDEUTSCHE GOLD- UND-SILBER-SCHEIDEANSTALT VORMALS ROESSLEB, OFFRANKFORT-ON-THE-MAIN, GERMANY, A CORPORATION OF GERMANY PROCESS FOR THEDESTRUCTIVE HYDROGENATION OF OABIBONACEOUS SUBSTANCES No Drawing.Original application filed October 24, 1928, Serial No. 314,849, and inGermany June 12, 1928. Divided and this application filed April 24,1930.. Serial No. 447,105.

, This application is a division of my earlier application S. N. 314,849which has now become Patent No. 1,852,988 dated April 5, 1932. Thisapplication is directed to the use of tungsten catalysts in a process ofdestructive hydrogenation resulting in increased yields because of theutilization of the Varga effect. In the use of tungsten catalysts, itdiffers from the molybdenum catalysts which are protected by Patent No.

The invention relates to the treatment of carbonaceous substances ofvarious kinds with hydrogen, or gases containing hydrogen or yieldinghydrogen under the reaction conditions, in which the initial substancesare converted into valuable,.mostly liquid, products by hydrogenation,reduction, or decomposition, or, if desired, by a plurality of theseoperations. The following are examples of initial substances suitablefor the destructive hydrogenation: fossil fuels such as mineral coal,brown coal, wood, peat, lignite etc; the products or constituents of theproducts obtained from these substances by distillation, extraction,hydrogenation, cracking, splitting up (decomposition) and other kinds oftreatment, such as the products from the carbonization of wood,tar-oils, brown coal-tar-oils, for example such as contain parailins andunsaturated compounds and the like; and, again, the furthertransformation products obtained, for example. by hydrogenation,cracking "etc. Other initial substances are, for example, mineral oilsand bitumens of various kinds such. for example,

as petrolcums, shale oils, asphalt, mineral wax cellulose, materialscontaining cellulose, materials containing lignin and the like, as wellas products obtained therefrom.

The hydrogenizing treatment of such initial substances has hithertomostly been carried out by subjecting them to the action of hydrogen, orgaseous mixtures containing hydrogen, under the usual pressure or a highpressure and at a high temperature in the absence or presence ofcatalysts. Sulfur and sulfur compounds have hitherto functioned in thisconnection as troublesome catalyst poisons and, consequently,sulfur-containing starting materials, e. g. tar oils; have had to besubjected before being hydrogenated to a troublesome and costlydesulfurizing process. Again, labor has been expended in the directionof discovering sulfur-proof catalysts which eliminate the detrimentaleffects of sulfur and sulfur compounds.

Exhaustive experiments have now led .to the surprising discovery that byusing an excess of hydrogen or gases containing hydrogen in excess oryielding hydrogen in excess under the conditions of the reaction,sulfuretted hydrogen, when usedin correct quantities, has in cooperationwith quite definite other catalysts, a very favorable catalytic effectupon the reaction when the reaction is carried out under high pressuresand at a high temperature. Instead of sul- 'furetted hydrogen,substances which, under the given reaction conditions, are adapted toform sulfuretted hydrogen may be employed. Substances yieldingsulfuretted hydrogen that come into consideration under the givenworking conditions are, inter alia, readily decomposable sulfurcompounds, for example, alkalior alkaline earth sulphides: alsosimilarly readily decomposable compounds containing the sulfur inorganic combination for example thiophene; and, furtheii, carbonbisulfide and, above all, sulfur itse If the treatment of the initialmaterials, for example, substances of the kind mentioned above, withhydrogen be carried out in the presence of suitable quantities ofsulfuretted hydrogen or suitable quantities of substances producingsulfuretted hydrogen and in the simultaneous presence of tungsten ortungsten compounds, advantages are obtained which are unobtainable withtungsten com- 90 pounds, by themselves. In particular, it is possible toprepare in this way technically pure hydrocarbon mixtures which can. beused directly, i. e. without further refining, as motor fuels,lubricating oils, solvents, starting materials for the organicindustries and so forth. Such products that are ob tainable by thepresent process owe their valuable properties to the fact that theyconsist almost entirely of saturated aliphatic, aromatic andhydro-aromatic hydrocarbons whilst "they are practically free fromcompounds containing oxygen, sulfur or nitrogen'and contain only quitesmall quantities of unsaturated hydrocarbons.

It is important for the success of the process that the sulfur duringthe reaction should be available in the form of sulfuretted hydrogen. Ithas, for example, been found that the combination of sulfur with heavymetals, for example with metals of the iron group in the form of theirsulfides, further the complete combination of sulfur with tungstenitself in the form of tungsten sulfides, prevents the realization of thedesired catalytic' result. Thus if, for example, tungsten acid andelementary sulfur are used as catalysts, it is necessary, for obtaininga favor able action, to use more sulfur than is necessary for theformation of the compound WS or WS If the operation is carried out innew reaction vessels, for example, of iron, the walls of which are stillcapable'of combining with appreciable quantities of sulfur, thisbehaviour must be taken into account by increasing the quantity ofsulfur or sulfur compounds adde The quantities of sulfuretted hydrogenfa vorable to the reaction are dependent among other things upon thenature particularly {upon the chemical properties of the material to betreated and the kind and'amount of thecatalysts employed in addition tothe sulfuretted hydrogen. Generally, these quantities range between 1and 15 parts of .sul-

furetted hydrogen to 100 parts of the initial material. When employing,-for example, 2 parts of tungstic acid to 100 parts of the startingmaterial, 1 to .,15 parts of sulfuretted hydrogen have been shown to beadvantageous. In many cases, amounts of 1 to 10 parts, preferably, 1 to6 parts have proved to be advantageous. The most suitable proportionswithin these limits of 1 to 10 parts must be specially selected for eachinitial substance. For example, in the case of beechwood tar-oil thepresence of 4 per cent of sulfuretted hydrogen during the reactionproved to be advantageous, whilst in the case of brown coal producertar-oil the desired effect was obtained in the presence of 1.5 per centof sulfuretted hydrogen. Less favorable results were obtained on goingbelow or exceeding these quantities.

When treating sulfur-containing initial materials, for example, taroils, the organically combined sulfur, which is adapted to producesulfuretted hydrogen under the conditions stated, must be taken intoaccount. Thus in these cases the added quantity of, for example, sulfurmust be such that the total quantity of the sulfuretted hydrogenavailable during the reaction falls within the limits within which theeffects favorable to the reaction are exerted.

The favorableaction of sulfuretted hydrogen consists as has beendiscovered, in the fact that it promotes the combination of hydrogen inthe case of olefines as well as in the case of unsaturated cyclichydrocarbons, and at the same time promotes also the splitting up of thesaturated hydrocarbons formed.v As a result, the formation of valuableproducts, chiefly of low boiling point and liquid, is promoted andundesired splitting up actions, for example, with the deposition of cokeand the formation of gas, is counteracted. The pe- .culiar action of thesulfuretted hydrogen arises, for example, in a particularly advantageousmanner in the hydrogenation of pitches and tar-oils, as, for example,beechwood tar-oil or brown coal tar-oil. If such starting materials arehydrogenated by employing the catalysts hitherto usual, thehydrogeriation products then contain always more or less largequantities of phenols, from which it is concluded that certainconstituents of these starting materials prevent the phenolreducing'action of the catalysts which would otherwise be good. Upon thecombined use of sulfuretted hydrogen with tungsten compounds, thereductionof phenol is, on the other hand, extraordinarily promoted owingto the presence of the sulfuretted hydrogen, so that the production ofproducts free from phenol is effected.

As mentioned above, the best eflects of the sulfuretted hydrogen occurwithin certain limits, dependent upon the starting materials and theworking conditions. Upon exceeding the limits, the favorable actions donot occur, while undesired effects, as, for example, polymerizationactions, may occur. Too great quantities of sulfuretted hydrogen shouldalso be avoided, because apart from polymerization effects and the like,other disadvantages also may occur, -for example, with relation to theremoval of sulfur from the final gases and regeneration of thesulfuretted hydrogen. The further examples given below serve as a basisfor the above explanations.

Further experiments have shown that the catalytic eflects of sulfurettedhydrogen or compounds producing sulfuretted hydrogen in conjunction withtungsten compoundse. g. tungstic acid or4tungstatescan be furtherheightened by the co-operationof auxiliary catalysts (activators). Suchauxiliary catalysts are, for example, boric acid and other compounds ofboron, e. g. borates. The efiicacy of these auxiliary catalysts isespecially evident when used in the treatment of paraifins andunsaturated compounds or products derived from these sub stances, forexample, brown coal tar-oils rich in parafiin. Certain chromiumcompounds may, for example, be employed as auxiliary catalysts, as, forexample, chromium hydrox-.

ide. Use of these auxiliary catalysts hasbeen proved desirable forexample in the production of products rich inparaflins. The efiicacy ofthe auxiliary catalysts is, among other things, dependent upon the kindof peratures generally lie between 250 and 7 00 0., preferably between350 and 550 (1, and the pressures employed above 50 atmospheres,preferably between 100 and 500 atmospheres. The reaction is generallycompleted within an hour. The hydrogen or the reducing gaseous mixturemust beemployed in fairlylarge excess, for example in such quantitiesthat thehydrogen present amounts to two or three times the quantity usedup in the destructive hydrogenation.

The most suitable proportionsare best de- I termined by experiment.Itmay be taken as a general rule that higher working temperaturesrequire larger aniounts of hydrogen in order to press back thedehydrogenation. Moreover, the conditions especially the proportions,should be so chosen that the highest pressure attained during thereaction is not less than 100 atmospheres. During the heating up processthe internal pressure rises to a maximum value (maximum pressure), whichas a rule is attained when the maximum temperature is, reached. 1 Hereafter, the'temperature remaining constant, the pressure again falls. Themaximum pressure has been found to be acharacteristic for the course ofthe reaction. l/Vhen the reaction has been completed the gases andvapours are allowed, to escape and, if desired, are condensed invariousfractions.

In continuous" working the initial substances, for example, in the formof gases. vapours, liquids or atomized liquid or solid substances. arepassed together with suitable amounts ofhydrogen or gases containinghydrogen and of sulfuretted hydrogen through an autoclave filled withthe solid catalyst and heated to the reaction temperature. Generally aworking pressure of 100 to 250 atmospheres is necessary in this case.Care should also be taken in this case that the pro portions of startingmaterial, hydrogen and the sulfuretted hydrogen, as well as the velocityof the stream of the whole. gas and vapour mixture through the reactionchamber, remain constant during the reaction or that the content ofsulfuretted hydrogen is kept during the operation within the limitsfavorable to the reaction.

Examples was heated at 460 for one hour with hydrogen of an initialpressure of 125 atm. in the presence of 8 per cent of tungstic acid and3 per cent of hydrogen sulfide. There re sulted 66 per cent ofoil havinga specific gravity of 0.849, of which 53.5 per cent. con

sisted of benzine boiling up to 180.

I (3) The same mineral coal distillation tar was heated at 460 for onehourwith hydrogen of an initial pressure of 125 atm. in the presence of4 per cent of tungstic acid, 4 per cent of molybdic acid and 2 per centof sulfur. There was obtained 74 per cent of oil having a specificgravity of 0.851, of which 50 per cent consisted of benzine boiling upto 180. (4?) English mineral coal tar was heated at 46 for one hour withhydrogen of an initial pressure of 125 atm. in the presence of 5 percent of tungsticacid, 5 per cent of molybdic acid and 8.5 ,per cent ofcarbon disulfide. There resulted 61 per cent of oil having a specificgravity of 0.914, of which 38 per cent consisted of benzine boiling upto 180.

(5) Technical tricresol with a sulfur content of 0.87 per cent washeated at 480 for one hour with hydrogen of an initial pressure of 105atm.in the presence of 5 per cent of tungstic acid and 2 per cent ofsulfur. There resulted 82 per cent of water clear oil with a specificgravity of 0.852,. of which 94 per cent distilled over up to 150.

The benzine obtained in accordance with the aforesaid examples isprecipitated in the distillation as a product being neither afl'ectedbylight nor by air and ready for use without any further purification.

I claim:

The method of destructive hydrogenation of carbonaceous substances,which consists of subjecting the substances to temperatures of from 250C. to 700 C. and pressures of from 100 to 500 atmospheres, and treatingthe sub:

stances with hydrogen in the presence-of tungsten catalyst and hydrogensulphide; so that hydrogen sulphide is continuously resent in optimalamounts between the limits J OSEF VARGA.

